Nearly every type of garment, other than those which are molded or knitted, requires seams. Equally so, nearly every type of garment which has been seamed together requires that there be some type of hem or cuff in the garment as well as a waistline of some sort. Seaming fabric together to form garments is a rather complicated task, and only highly skilled operators, after prolonged training, are used for such operations. It requires even greater skill from the operator to ensure that the bottom edges (cuffs or hems) and top ends (waistband, etc.) are straight and even with respect to each other during and after sewing of the garment's seams.
While there have been a number of machines which have attempted to match the cuff of garments which are sewn together with side seams, by far the most widely used and near accurate method has been to manually match the bottoms and top ends of the fabric by pulling and stretching one piece of the fabric relative to the other piece and then holding the ends together so that the cuff, waist and seams come out even. Notwithstanding the widespread manual method for accomplishing the task of aligning the top and bottom ends of side seams of fabric, there are a number of apparatuses (some semi-automatic) which have been used in an attempt to accomplish this difficult task.
A number of prior art patented devices have been directed toward applying a continuous tension and stretch to both panels of the garment in an attempt to make them even as they approach the sewing station. For example, U.S. Pat. Nos. 3,717,408; 3,905,316; 4,013,025; 4,036,156; 4,062,309; and 4,086,860 are directed to such devices. Each of these references in some way applies an undetermined amount of tension and stretch to the two panels of fabric by gripping them at one end with a clamp or some other means of securing the fabric while tension is applied and then pulls the fabric in the direction opposite the clamp in an effort to stretch the two panel ends even. None of the apparatuses set forth in any of the aforementioned patents discloses a means for monitoring the actual length of two pieces of fabric and then correcting for that discrepancy in conjunction with sewing head feeding, without applying any unnecessary tension, stretch or other pressure on both panels of fabric. Similarly, the prior art devices are not accurate in their manner of correcting the mismatch of fabric lengths and as such necessarily result in a lot of guesswork as well as unnecessary tension being applied to the fabric. These prior art devices are largely dependent on the skill of the worker and thus result in too much variance and chance for error.
Still another common problem in most prior art methods and apparatuses used to match panel ends results from the pull of the bottom panel by the bottom feed dog in typical sewing machines. That is the bottom feed dog pulls the bottom panel more than the top panel is pulled by the smooth non-driven presser foot which comes into contact with the top panel. The presser foot does not have gripping teeth like the bottom feed dog. Thus, a method is needed to match panel ends which recognizes this known problem which results when the bottom feed dog exerts this pull on the bottom panel.
Despite the available patented devices, it is apparent that the most widely used method of matching a pair of fabric workpieces prior to sewing them along their seams is to manually manipulate the workpieces by independently pulling and stretching them, one relative to another, and subsequently feeding both workpieces into the workstation where they are sewn together as tension is continuously applied to them manually to make sure that the cuff and the waist come out even. This manual method is further frustrated by the unequal pull which is exerted on the bottom panel by the bottom feed dog.